21310308373 has 2 divisors, whose sum is σ = 21310308374. Its totient is φ = 21310308372.

The previous prime is 21310308359. The next prime is 21310308389. The reversal of 21310308373 is 37380301312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11898010084 + 9412298289 = 109078^2 + 97017^2 .

It is a cyclic number.

It is not a de Polignac number, because 21310308373 - 2⁹ = 21310307861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21310308343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655154186 + 10655154187.

It is an arithmetic number, because the mean of its divisors is an integer number (10655154187).

Almost surely, 2^21310308373 is an apocalyptic number.

It is an amenable number.

21310308373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21310308373 is an equidigital number, since it uses as much as digits as its factorization.

21310308373 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 31.

Adding to 21310308373 its reverse (37380301312), we get a palindrome (58690609685).

The spelling of 21310308373 in words is "twenty-one billion, three hundred ten million, three hundred eight thousand, three hundred seventy-three".